Beat the butter with the sugar. Add the eggs one by one and beat until smooth. Dissolve the yeast in a little warm water with a little flour. Add to the eggs with a little more flour and mix well.
Add lemon zest, vanilla, brandy, orange blossom water and malt extract. Beat in the remaining flour until a dough consistency is reached.
Add the nuts, mixed fruit and chocolate and knead well. When well kneaded let rise, covered, in a warm place until doubled in volume.
Grease four paper panettone molds. Divide the dough into four between the molds. Let rise another half hour while preheating the oven to 180 degrees C. Cut an X into the top of each and brush with melted butter.